The invention relates to a method of manufacturing a video magnetic head having a sputtered gap region, in which the magnetic core consists of two soft magnetic core halves with a non-magnetic gap in between. An abrasion-resistant soft magnetic layer is sputtered by means of a maqnetron sputtering apparatus in the region between the gap and the core halves as well as between the gap and a glass inclusion.
With the advance in electronic technology magnetic materials composed of layers have gained general recognition in several technical fields and play an important role in the field of magnetic heads used for magnetic recording.
It is known that particularly video magnetic heads are composed in the form of layers of a magnetic oxide material such as polycrystalline ferrite and a magnetic material such as monocrystalline sendust. The magnetic heads may be formed with longitudinally arranged layers so that, for example a magnetic core of sendust is combined with a support of a magnetic material such as ferrite. Magnetic heads having different material layers are required in order to comply with stringent technical requirements. Recording media having a high coercive force have been developed such as metal tapes and metal tapes with vapour deposited layers in order to comply with the requirements of a high magnetic recording density. This development has been accompanied by a very intensive development of magnetic materials for magnetic heads. Since a magnetic head with a magnetic core made of simple magnetic materials has various drawbacks, a magnetic head was proposed which uses composite magnetic materials such as a magnetic metal core of sendust which is included between a magnetic oxide core of ferrite.
There are also magnetic heads with a layer construction in which the magnetic core only has a thin layer of Sendust in the gap region This layer is sputtered by means of various sputtering techniques. The use of a magnetron sputtering apparatus is advantageous because the desired layer thickness can be achieved therewith. It is, however, a drawback that the thickness of the alloy support--target--must remain relatively thin, usually thinner than 3 mm, for the alloy with a suitable magnetic property to be used and that for physical reasons only a small part of the target surface is sputtered so that target consumption is high. Thicker targets, which can more economically be processed, cannot be used for technical reasons for the alloys having a suitable magnetic property.